In the operation of an internal combustion engine, a part of gases in a combustion chamber may enter a crankcase via a gap between a piston ring and a cylinder liner. This part of gases contains lubricating oil mist and combustion products produced from the combustion in the combustion chamber.
In order to reduce a rate of oil consumption and exhaust clean emissions, oil is required to be separated from the gases when the gases entered the crankcase. A common oil-gas separator employed in an internal combustion engine is relatively simple, which generally includes a housing and a stationary filter element disposed in the housing. After an oil-gas mixture enters the oil-gas separator, an oil droplet is absorbed by the filter element, and gas is discharged from the housing after passing through the filter element.
As is well known, for pursuing a high oil-gas separating rate, resistance provided by the filter element is required to be increased, however, this may cause an increased pressure in the crankcase, which is apt to cause oil leakage of the crankcase. Further, since all oil droplets in the oil-gas mixture are absorbed onto the stationary filter element, the stationary filter element has a short service life, which is required to be replaced frequently.
Therefore, a technical issue to be addressed by the person skilled in the art presently is to enhance oil-gas separating effect while not increasing pressure of the gas in the crankcase, and improve service life of the filter element.